SAP Webdynpro Introduction

 SAP Webdynpro Introduction

Web Dynpro for ABAP is the SAP standard UI technology for developing Web applications in the ABAP environment.

Every Web Dynpro sap application is structured according to the Model View Controller programming model: The model forms the interface to the back end system and thus enables the Web Dynpro sap application access to data.

The controller formats the model data to be displayed in the view, processes the user entries made by the user, and returns them to the model.

As an independent program unit it connects a URL that can be accessed by the user with a window in the Web Dynpro sap component.

Before learning about the Controllers let us know something about different types of interfaces that are created at the time of creation of the component.

The interface begin with the prefix IG is used for cross controller communication.(E.g View controller to component controller) There is only one component controller exists per webdynpro sap component and it is global.

i.e Component controller consist of data and processing logic that is available to all the views in the component.

The life time of the component controller is the life time of the component.

Components of Component controller: Custom controllers can be additionally created in the component and there are exactly similar to the component controller in terms of functionality.

This means it is visible to all the elements in the component and life time of the controller is the lifetime of the component.

Any number of custom controllers can be created in the component and it provides the option of structuring the data's and functions.

It only makes sense to create a custom controller if certain function and data's are to be associated with the specific set of views.

The first three components Properties, Context and Attributes are similarly to that of component controller and the only differ in the events and method properties.

Interface controller is used for cross component communication.

Components of interface Controller: Each view exactly consists of one view controller.

No of view controllers in a component depends upon the no of views.

The view controller cares about the view specific flow logic like checking user input, handling user actions etc.

The lifetime of the view controller is restricted to the life time of the view.

Components of view Controller: It is visible throughout the component and behaves like component or custom controller.

Generally in Web Dynpro ABAP, we write all the required logic within the component itself but we can write the necessary logic outside the component that is in a class and we can use that class as the assistance class in our Web Dynpro component.

Each local controller interface has a fixed number of methods that can only be called by the runtime.

Version management is active for all objects of the ABAP Workbench.

Version management serves different purposes and user groups: You can access version management from the following: In particular, you can measure Web Dynpro ABAP and BSP applications, as well as ABAP Web services.

The Performance Trace allows you to record database access, locking activities, remote calls of reports and transactions, and table buffer calls from the SAP system in a trace file and to display the performance log as a list.

The Performance Trace is fully integrated in the ABAP Workbench, and can be called from the ABAP Workbench initial screen.

To use the Performance Trace, you need authorization to start Transaction ST05 and the system authorizations "Change trace switches" (authorization STOM for authorization object S_ADMI_FCD) and "Analyze traces" (authorization STOR, also for authorization object S_ADMI_FCD).

Table buffer trace: You can use this to monitor database calls of reports and transactions made via the table buffer.

We can also choose Program Check Extended program check.

The extended program check takes considerably longer time than other checks but it uses a buffer and the process speeds up after the first run.

All ABAP programs are modular in structure and made up of processing blocks (see Structure of ABAP Programs).

There are two kinds of processing blocks, those that are called from outside a program by the ABAP runtime system, and those that can be called by ABAP statements in ABAP programs.

Processing blocks that are called using the ABAP runtime system: Processing blocks that are called from ABAP programs: The processing blocks that you call from ABAP programs are called procedures.

As well as modularization in processing blocks, ABAP allows you to modularize source code by placing ABAP statements either in local macros or global include programs.

This kind of modularization makes ABAP programs easier to read and maintain, as well as avoiding redundancy, increasing the reusability of source code, and encapsulating data.

Splitting up ABAP programs into event blocks and dialog modules is designed to help the general flow of the programs.

In this article, we will learn how to create the active version in version database and why it's important.

Background: Whenever we work on any ABAP developments, we do it in development system.

Once we move the changes to non-prod systems, it creates the version in the version database of the development system.

Hence, generating the version during the development itself is very important to have the backup created for us in case of disaster.

1) Create the simple report and look at the version management tab.

Click on the tab Utilities -> Versions-> Version Management and then the following screen will appear.

We can see that there is no version available in the version database.

However, we can see the version available in development database.

2) Create the version in Version Database Click on the Utilities ->Versions -> Generate Version Now, check the newly created version is exists in version database or not.

Advantages of creating the version in version database: This cannot be done if we don't have any active version in version database.

Let's say we have created the version in version database.

Put the exact program name and click on version management and click on retrieve button.

You will be provided with the pop up message saying that current version of the program will be overwritten by an older version.

In the version management, there will be 2 versions in the development database.

Activate the report and it will also delete one of the versions from development database and keep only one active version which is ready for your use.

Note: When we move the changes from development system to non-prod (then to prod), the version gets automatically created to the version database.

Please try to retrieve the deleted report without creating the version in version database.

Then you will come to know the importance of creating the versions while developing the big reports.

Display The display mode of the ABAP Editor is used for displaying a version.

Using the editor functions (clipboard) you can copy parts of an older version or the entire version to another window.

Both versions are displayed in their entirety.

Only the parts in which both versions differ are displayed.

Dictionary objects: This function is active if you call version management from object maintenance while in change mode.

When you save your changes, the active version is overwritten with the content in the editor.

For security reasons, the system creates a temporary version of the status active before the retrieval which is saved in version management.

When you change the object, you must either have created a request, or the system prompts you to choose or create a request once you save your changes.

The system first creates a temporary version of the active version.

The active version is then overwritten with the version retrieved.

REMOTE comparison compares the object with a version from a different system.